1. Field of the Invention
The present invention relates to bearing apparatus for supporting a rotor shaft of a rotary compressor provided with a housing, a rotor contained in the housing, a plurality of vanes movably fitted in the rotor.
2. Description of the Prior Art
In general, a compressor has a rotor shaft rotatably supported by a bearing with grease lubrication. However, the bearing has a relatively short life. This is a fatal defect for the movable vane compressor used as a supercharger in an automobile engine. The short life results from poor lubrication or lack of bearing grease in the bearing.
Air is compressed within the compression working space between two adjacent vanes in the compressor. A part of the compressed air enters an annular clearance between the inner side surface of the bearing and the side surface of the rotor and, then, passes through the bearing to push the grease outwardly therefrom, resulting in that the bearing is poor in lubrication due to a lack of bearing grease.